The present invention relates to an improved hydraulic servovalve construction which will provide a relatively large capacity and yet have a relatively small size.
By way of background, in the past the size of a servovalve varied generally directly with its capacity, and various factors affected the size and capacity of a servovalve. A prior servovalve generally required a sleeve surrounding the spool for providing a proper fluid flow path through the valve body. Therefore, to obtain a desired spool driving force at a predetermined fluid pressure with a given size of spool, the size of the valve body of the spool had to be relatively large to accommodate the sleeve. In addition, the flow of fluid through a prior servovalve for operating a remote device was only through grooves around the spool of the servovalve. This limited the amount of fluid flowing through the valve body, and thus limited the capacity of the servovalve. Therefore, in order to obtain a greater fluid flow, the size of the spool had to be increased, which, in turn, increased the size of the valve body. In addition, the orientation of the various components of a prior servovalve including the spool bore and filter bore and the torque motor was such that the entire servovalve was relatively large.